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    <title>Document</title>
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    <script>
        // 1、打印100以内的所偶数 的 和
        var num = 0
        for(var i = 0; i <= 100 ;i++){
            if(i % 2 === 0){
                num += i
            }
        }
        console.log('100以内偶数之和为' + num)
    </script>
</body>
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